I am a bit confused here, since the blockchain of the Bitcoin is public, anyone can get the complete transactions of the Bitcoin. If someone knows your wallet address, he can look all the transactions you made and where your Bitcoins flow to.
It won't be difficult to write an analysis software, to find out the links among wallets, and the usage of bitcoins. So from this sense, there's no real anonymity with Bitcoin. Do I miss something there?
Try to tie the bitcoin address to a person. Thats the hard part.
Yes, their is definitly a "paper trail" but not much more than that.